McMillen designed two facilities—a temporary upstream “trap-and-haul” facility that operates during the dam construction to provide interim upstream fish passage and gain insight to improve the design of a permanent fishway trap-and-haul facility and a permanent fishway that provides upstream fish passage at the outlet of the generating station, following closure of the diversion tunnels and reservoir filling.
McMillen completed the design for the temporary facility to provide upstream passage while the new dam was being built. It has been in operation since 2020 and has successfully passed small-bodied fish such as Shiner, Graying, Sculpin, and several large-bodied fish. The fish population in the river was similar to that of the fishway, indicating that the fishway is sized for target and resident fish alike. The operation of the temporary facility has provided some lessons learned, which have been implemented in the design of the permanent facility to increase its adaptability to changing environments.
The design of the permanent upstream fish collection facility has been completed and will provide safe and efficient fish transport from the tailrace to the upstream release locations after the diversion phase. Construction of the permanent facility is reaching completion, with operation expected to start in the spring of 2024.
McMillen’s team completed the following tasks:
• Alternatives analysis with considerations for potential fish passage risks, technical feasibility, biological
benefits, and capital and operating costs
• Conceptual design analysis and report
• Construction cost estimates and schedule
• Constructability reviews
• Design reports including the Conceptual (CDR), Definition (DDR), and Implementation Design Report (IDR)
• Full drawings and specifications for construction of both facilities
• Project management tasks such as regular coordination meetings, document control, and day-to-day
management of work execution, including preparation of an initial work plan
• Technical advice on procurement for construction
• Biological monitoring plan
• Hydrologic and hydraulic analysis with computational fluid dynamic (CFD) modeling to determine the
facility’s attraction flow and other aspects
• Geotechnical review
• Engineering support during construction
• Owner’s engineer services during construction, commissioning, and initial years of operation on the temporary facility
• Technical support for permitting, discussions with regulators, and consultation with the 13 Indigenous groups in the vicinity
